Name: mf23781 Date: 08/24/98


*Test case:

J17_13a_MyThread.java
=========================

class J17_13a_MyThread extends Thread {
  J17_13a_SharedResource r;



  public J17_13a_MyThread(J17_13a_SharedResource r) {this.r = r;}

  public void run() { //LOC:TC0003.01
for (int i=0; i<3; i++) {
try {
r.Increment(); //LOC:TC0002.01
Thread.sleep(100);
}
catch (InterruptedException e) {}
}
  }

}


J17_13a_SharedResource.java
=============================


class J17_13a_SharedResource {
  private int x=0; //observe the value of x;



//it should be changing 1..2..3
  
  public synchronized void Increment () {
x++;
System.out.println(x);
  }

}


J17_13a_ThreadsAndLocks.java
=============================


//Author: Henry Chiu
//Date: 19980219
//17.13
//The synchronized statement (§14.17) computes
//a reference to an object; it then attempts to
//perform a lock action on that object and does
//not proceed further until the lock action has successfully
// completed. (A lock action may be delayed because
//the rules about locks can prevent the main memory
//from participating until some other thread is ready
//to perform one or more unlock actions.) After the lock
//action has been performed, the body of the synchronized
//statement is executed. If execution of the body is ever
//completed, either normally or abruptly, an unlock action
//is automatically performed on that same lock.
//A synchronized method (§8.4.3.5) automatically
//performs a lock action when it is invoked; its body
//is not executed until the lock action has successfully
//completed. If the method is an instance method, it locks
//the lock associated with the instance for which it was
//invoked (that is, the object that will be known as this
//during execution of the body of the method).
//Cross Reference: 17.2, 17.5


public class J17_13a_ThreadsAndLocks
{
  public int x;

  public static void main(String args[]) {
J17_13a_SharedResource r = new J17_13a_SharedResource();
Thread t1 = new J17_13a_MyThread(r);
Thread t2 = new J17_13a_MyThread(r);
t1.start();
t2.start();
  }

}


*Steps to reproduce the defect:

jdb J17_13a_ThreadsAndLocks
stop at J17_13a_SharedResource:10
run
run
thread 2 (to switch to the thread that is suspended)
next




*Outputs:

1.1.6
===========

P:\defects\6433>jdb J17_13a_ThreadsAndLocks
Initializing jdb...
Warning: JIT compiler "symcjit" not found. Will use interpreter.
Warning: JIT compiler "symcjit" not found. Will use interpreter.
0xf8fa20:class(J17_13a_ThreadsAndLocks)
> stop at J17_13a_SharedResource:10
Breakpoint set at J17_13a_SharedResource:10
> run
run J17_13a_ThreadsAndLocks
running ...
main[1]
Breakpoint hit: J17_13a_SharedResource.Increment (J17_13a_SharedResource:10)
Thread-96[1] run
run J17_13a_ThreadsAndLocks
running ...
main[1]
Breakpoint hit: J17_13a_SharedResource.Increment (J17_13a_SharedResource:10)
Thread-99[1] thread 2
Thread-100[1] next
Thread-100[1]
Fatal exception: java.net.SocketException: Connection reset by peer
java.net.SocketException: Connection reset by peer
        at java.net.SocketInputStream.read(Compiled Code)
        at java.io.BufferedInputStream.fill(Compiled Code)
        at java.io.BufferedInputStream.read(Compiled Code)
        at java.io.FilterInputStream.read(FilterInputStream.java:81)
        at sun.tools.debug.AgentIn.run(Compiled Code)
        at java.lang.Thread.run(Thread.java:474)

J17_13a_ThreadsAndLocks exited


1.1.7H
=========


P:\defects\6433>jdb J17_13a_ThreadsAndLocks
Initializing jdb...
0xf8ff78:class(J17_13a_ThreadsAndLocks)
> stop at J17_13a_SharedResource:10
Breakpoint set at J17_13a_SharedResource:10
> run
run J17_13a_ThreadsAndLocks
running ...
main[1]
Breakpoint hit: J17_13a_SharedResource.Increment (J17_13a_SharedResource:10)
Thread-95[1] run
run J17_13a_ThreadsAndLocks
running ...
main[1]
Breakpoint hit: J17_13a_SharedResource.Increment (J17_13a_SharedResource:10)
Thread-98[1] thread 2
Thread-99[1] next
Thread-99[1]
Fatal exception: java.net.SocketException: Connection reset by peer
java.net.SocketException: Connection reset by peer
        at java.net.SocketInputStream.read(Compiled Code)
        at java.io.BufferedInputStream.fill(Compiled Code)
        at java.io.BufferedInputStream.read(Compiled Code)
        at java.io.FilterInputStream.read(FilterInputStream.java:73)
        at sun.tools.debug.AgentIn.run(Compiled Code)
        at java.lang.Thread.run(Thread.java:466)

J17_13a_ThreadsAndLocks exited


1.2fcs-E(First run)
===================

P:\defects\6433>jdb J17_13a_ThreadsAndLocks
Initializing jdb...
0xa9:class(J17_13a_ThreadsAndLocks)
> stop at J17_13a_SharedResource:10
Breakpoint set at J17_13a_SharedResource:10
> run
run J17_13a_ThreadsAndLocks
running ...
Thread-0[1]
Breakpoint hit: J17_13a_SharedResource.Increment (J17_13a_SharedResource:10)
Thread-0[1] run
run J17_13a_ThreadsAndLocks
running ...
main[1]
Current thread "main" died. Execution continuing...
>
Breakpoint hit: J17_13a_SharedResource.Increment (J17_13a_SharedResource:10)
Thread-3[1] thread 2
Thread-4[1] next
java.lang.InternalError: JVMDI_ERROR_NO_MORE_FRAMESThread-4[1]
        at sun.tools.agent.StackFrame.frameCount(Native Method)
        at sun.tools.agent.StackFrame.getStackFrames(StackFrame.java:47)
        at sun.tools.agent.StepHandler.getCurrentStackTrace(StepHandler.java:407)
        at sun.tools.agent.StepHandler.stepLine(StepHandler.java:731)
        at sun.tools.agent.StepHandler.run(StepHandler.java:156)


1.2fcs-E(Second run)
====================

P:\defects\6433>jdb J17_13a_ThreadsAndLocks
Initializing jdb...
0xa9:class(J17_13a_ThreadsAndLocks)
> stop at J17_13a_SharedResource:10
Breakpoint set at J17_13a_SharedResource:10
> run
run J17_13a_ThreadsAndLocks
running ...
main[1]
Current thread "main" died. Execution continuing...
>
Breakpoint hit: J17_13a_SharedResource.Increment (J17_13a_SharedResource:10)
Thread-0[1] run
run J17_13a_ThreadsAndLocks
running ...
main[1]
Breakpoint hit:
Fatal exception: java.lang.Exception: java.lang.InternalError: JVMDI_ERROR_INVALID_TH
READ
java.lang.Exception: java.lang.InternalError: JVMDI_ERROR_INVALID_THREAD
        at sun.tools.debug.RemoteAgent.getReply(Compiled Code)
        at sun.tools.debug.RemoteAgent.dumpStack(Compiled Code)
        at sun.tools.debug.RemoteThread.getStack(RemoteThread.java:278)
        at sun.tools.debug.RemoteThread.dumpStack(RemoteThread.java:129)
        at sun.tools.ttydebug.TTY.breakpointEvent(TTY.java:80)
        at sun.tools.debug.AgentIn.run(Compiled Code)
        at java.lang.Thread.run(Thread.java:475)

J17_13a_ThreadsAndLocks exited

======================================================================